Door positioning apparatus



Nov. 29, 1955 E. J. BARNETT 2,725,052

DOOR POSITIONING APPARATUS Filed April 17, 1953 3 Sheets-Sheet 1 FIG. I.

lNVENTOR EUGENE J. BARNETT ATTORNEY DOOR POSITIONING APPARATUS 3 Sheetswsheet Filed April INVENTOR EUGENE J. BARNETT ATTORNEY FIG. 3.

NW 29, 11955 E. J. BARNETT gfififisz DOOR POSITIONING APPARATUS File pr l 7, 1953 5 Sheets-Sheet 3 INVENTOR EUGENE J. BARNETT ATTORNEY United States Patent DOOR POSITIONING APPARATUS Eugene J. Barnett, Mansfield, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application April 17, 1953, Serial No. 349,449

6 Claims. (Cl. 126- 191) This invention relates to a door positioning mechanism, more particularly to an oven door positioning mechanism having means for providing a broil or partially ajar position for the door.

It is an object of the invention to provide an improved and simplified door positioning mechanism for holding an oven door in the broil position and the closed position and for counterbalancing the door when it is opened beyond the broil position.

It is a further object to provide an oven door positioning mechanism which may be manufactured economically and easily by mass production methods and requiring a minimum of adjustment at the time of assembly.

In accordance with my invention, I provide a mechanism which includes a single spring connected to an oven door by two lost motion connections. The first lost motion connection is effective to impose spring force on the door in closing direction when the door is in the broil position or any other more fully open position.

The second lost motion connection is effective to transmit spring force when the door is in the broil position, the fully closed position or any position intermediate these two positions. The spring force transmitted through the second lost motion connection is imposed on a cam follower which engages a cam surface sloped to bias the door in closing direction when the door is near closed position and to engage a cam sloped to bias the door in opening direction as the door approaches the broil posi tion.

At the broil position, the lost motions of the two connections are taken up and spring force is transmitted through both connections to bias the door in opposing directions, thereby resiliently retaining the same in the broil position.

The two lost motion connections are arranged to be biased by a straight line pull on the spring regardless of the position of the door, thereby considerably simplifying the mechanism.

The above and the objects are effected by the invention as will be apparent from the following description taken in connection with the accompanying drawings, forming a part of this application, in which:

Fig. l is a fragmentary vertical sectional view showing an oven door structure having my invention incorporated therein, the door beingshown in the closed position;

Fig. 2 is a section taken on line IIII of Fig. 1;

Fig. 3 is a fragmentary view similar to Fig. 1, but on a reduced scale and showing the door in the broil position;

Fig. 4 is a view similar to Fig. 3, but showing the door in an almost fully open position;

Figs. 5, 6 and 7 are fragmentary vertical sectional views of another embodiment of my invention, the door being shown in the closed, broil and almost fully open positions, respectively; and I Fig. 8 is a vertical section taken on line VIII-VIII of Fig. 7.

Referring to the drawings in detail, especially Figs. 1 and 2, there is shown a door positioning mechanism 8 for a door 10 which serves to close the access opening 11 provided in an oven liner 12. The oven liner 12 is inserted through an opening provided in a front panel 14 of a range body or the like. The door 10 is' hingeably mounted on a hinge bracket 18 by a hinge pin 20 attached to the lower portion of the door 10 with its axis substantially horizontal. Thus, the door 10 is movable about a horizontal axis.

The hinge bracket 18 may be formed of stamped sheet metal and is provided with an L-shaped upper portion 21 for receiving the hinge pin 20 and a downwardly extending portion 22 received behind the panel 14, the

panel 14 being provided with a slot 24 for reception of the L-shaped portion 21 therethrough.

The portion 22 of the hinge bracket is supportedat its lower end by a leaf spring member 26, which is attached at its lower end to the panel 14 by means of nuts and screws 28. An adjusting screw 30 passing through the panel 14 is received in threaded engagement with the hinge bracket portion 22 and serves, by adjustment, to shift the hinge bracket 18 to the left or to the right, as desired. A bowed compression spring member 36 is interposed between the panel 14 and the bracket portion 22.

With this arrangement, the hinge pin 20 may be shifted to the left or right, as necessary to permit the door to properly seal the access opening 11, by rotating the screw 30.

The door 10 is further provided with a blade 40 attached thereto at one end and extending through the panel slot 24 to the interior of the range body adjacent the oven liner 12. The blade 40 is of generally arcuate shape, so

L that it will pass through the slot 24 when the door is opened. As shown in Fig. 1, the free end of the blade 40 is formed into a hook 42, which is open at the top and serves to connect the blade 40 to a heavy helically wound spring 44 for counterbalancing the weight of the door, i. e., for imparting a turning moment on the door in closing direction.

The spring 44 has its lower end fastened to the range body (as shown in Fig. 4) by means of a bracket 46 and its upper end is connectible to the blade hook 42 by a hook 48 formed at the upper end of a wire link 50 and extending about the inner edge 53 of the blade 40. The hook 48 and the blade hook 42 comprise a first lost motion connection. The link 50 is connected to the spring 44 by a lower hook 54 which is hooked into an adjusting plate 56 made of sheet material threadedly engaging the end convolutions of the spring.

The blade 40 has a pair of cam surfaces 57 and 58 of opposite slope meeting each other at a rounded apex portion 59. A roller 60, disposed adjacent the cam surfaces 57 and 58, is mounted on a pin 62 and is preferably freely rotatable thereon. The roller acts as a cam follower and is biased into engagement with one or the other of the cam surfaces byv the spring 44. When the roller engages cam surface 57, as shown in Fig. l, the door is biased to the closed position, while when the roller engages the cam surface 58, as shown in Fig. 3, the door is biased in opening direction to the broil position. The roller 60 is connected to the spring 44 by means of a U-shaped yoke 64 and the wire link 50. The roller 60 is supported by a bracket 66 having a pair of oppositely-disposed sides 68. The bracket 66 has a central portion 70 by means of which it is attached to the panel 14. The bracket side portions 68 are provided with a pair of vertically-elongated slots 72 which receive and guide the roller pin 62. The yoke 64 has a pair of elongated side members 74 joined at the bottom by a short connecting portion 76 and is pivotally-mounted at its upper end to the .pin 62.

The link t} passes through an opening in the connecting portion. 76v of the. yoke and is freely slidable therethrough. The link St has a collar 78 rigidly fastened thereto in a position to abut the connecting portion 76 of the yoke to impart the previously mentioned downward bias on the roller 6%, under certain conditions subsequently to be described. The collar 78 and the connecting portion 76 of the yoke comprise a second lost motion connection.

The link 50 constitutes the abutment member or means, the connecting member and the lost motion means referred to in the claims. The collar 78 provides the abutment engaging the connecting portion 76 of the yoke, the latter being referred to in some of the claims as a spring force transmitting member.

' Operation (Figs. 1-4

The door positioning mechanism operates as follows: When the door 10 is in the closed position, as shown in Fig. 1, the roller oil isin contact with the cam surface 57 of the blade and the collar 78 is in contact with the connecting portion 76 of the yoke. A downward spring force is exerted on the roller by the spring 44, this force being transmitted through the link 5% to the collar '78, to the portion 76 of the yoke, and through the yoke sides 7% to the roller 6% Since the cam surface 57 slopes upwardly to the right, the downward bias exerted by the roller 69 on the cam surface 57 provides a component force vector to the right, resulting in a turning moment in clockwise direction urging the doorto the closed position. It will be noted that, in this position, the entire spring force is exerted on the cam surface '57-.

As shown in Fig. 3, the door is in the slightly ajar 0r broil position. This position is attained by pulling the door outwardly from the c'iosed position against the force of the spring until the roller 6% passes over the apex 59 onto the cam surface 58, whereupon the bias of the spring 44 becomes effective to provide a turning moment in counterclockwise direction, thereby moving the door in opening direction. As the door moves to the left, the blade 4%) is rotated counterclockwise until its hook 42 moves into engagement with the hook 4S on the link 50. The force of the spring 44 exerted on the blade 45 through the hook 42 is effective to impose a turning moment in clockwise direction, urging the door in closing direction and opposing the countercrockwise moment mentioned above. The lost motion between the two lost motion connections is taken up when the door is in the broil positron, at which time the moment in door-closing direction is initiated to oppose and balance the moment in dooropening direction to hold the door in the broil position. The slightly ajar position described above is thus automatically attained merely by opening the door sufiiciently to allow the roller 66 to pass over the apex portion 59.

As the door is opened beyond the broil position, the blade hook 42 rises and lifts the collar 78 out of engagement with the yoke to terminate the counterclockwise turning moment and increase the clockwise turning moment on the door. Thus, should the door be pulled further to the left by the operator and then released, the spring forces acting on the door through the blade will be eifective to return the door tothe same slightly ajar position.

When the door is moved beyond the broil position to the fully open position, it passes through thestage shown in Fig. 4. As previously mentioned, when the force of the spring 44 acts on the door through the hook 42, the force is exerted in door-closing direction and serves to counterbalance the weight of the door. The yoke 64 is suspended in the bracket 66 by the roller pin 62. Hence, when the roller 69 is separated from the blade 40, the pin 62 drops to the bottom of the slots 72 in the bracket andsupports the yoke in suspended position. When the door is opened beyond the broil position, the yoke. 64 merely swings, about the. center of the pin 62 and its lower end moves slightly to the right as, shown in Fig. 4, as guided by the link 5i Further movement of the door to the left causes the spring 44 to be expanded further.

The blade 40 is further provided with an extended stop portion 79 of sufiicient length to abut any desired stationary structural portion when the door is moved to the fully open position. Although this position has not been shown, it is common practice to limit the fully open position of the door to a substantially horizontal plane. Also, the spring 44' and the blade 40 are preferably designed so that, when the door is in the fully open position, its weight exerts a force in excess of the counterbalancing force, thereby maintaining the door in the fully open position.

When the door is moved in closing direction from the fully open position, the sequence of operation is substantially reversed. The door is raised manually and may be passed without interruption through the position shown in Fig. 4 to the broil position shown in Fig. 3. During this portion of its movement, the spring force is applied to the blade hook 42 to urge the door in closing direction and the stop collar 78 is out of engagement with the yoke 64.

Upon approaching the broil position, the cam surface 58. is brought into contact with the roller 60, causing the yoke to rise, thereby bringing its connecting portion 76 into engagement with the stop collar 78. The force of the spring is again partially transferred to the roller. to impose a turning moment in door opening direction which, in the broil position, balances the turning moment in door closing direction exerted through the. blade hook 42.

To move the door past the broil position to the closed position shown in Fig. 1, the door isv manually moved in closing direction until the roller 60 rides over the apex portion 59 to the cam surface 57. At the beginning of such movement, the hook 42 becomes disengaged from the hook 48 and the entire force of the spring is exerted on the cam surface 58 through the roller to impose a turning moment in opening, direction tending to return the door to the broil position. During the latter portion of such movement, the entire spring force is exerted on the cam surface 57 through the roller to impose a turning moment in closing direction sufficient to keep the door tightly closed.

It will be noted that the hook 4d on the rink 5!] is made sufiiciently long to loosely engage the sides of the blade 40 when the door is in the closed position, thereby eliminating the possibility of detachment therefrom.

It will now be seen that the various turning moments exerted on the door to position the same as above described are. attained by means of the single spring 44. Also, by referring to Figs. 1 through 4, it will be seen that the pull on the spring 44 is always in a straight line, regardless. of the positionof the door.

Figs. 5 to 8 Figs. 5 through 8, inclusive, show a second embodiment in which the roller 69 isdisposed below the level of the door pivot pin 2b. In this. embodiment, it is desired to apply the downward force of the spring 44 to the roller in a substantially horizontal direction and to this end the roller is rotatably mounted on a bell crank lever 80 which is incorporated in the second lost motion connection. The lever 80, as illustrated in Fig. 8, is of U-shape having a pair of side portions 82 joined by a. connecting portion 83. The roller, 60 is supported between the side portions 82 of the lever by a pivot pin 84. A hinge bracket 18, similar, to that shown in the first embodiment, but having a horizontal flange 86 disposed below theoven liner 12', serves to pivotally support the door 10 and the lever 80. The lever 80 is pivotally attached to the flange 86 of the hinge bracket by a pivot pin 87. The bracket flange 86 isfurther travel. The lever 80 is narrower in width ,than the pin 87 and is freely slidable transversely thereon, as dictated by the link 50. Thus, the roller 60 is self centering upon the cam surfaces 57' and 58'.

A blade 40', attached to the door 10, is provided with a first cam surface 57' and a second cam surface 58 of opposite slopes joined together by an arcuate apex portion 59.

Operation (Figs. 5-8) When the door is in the closed position, as shown in Fig. 5, the hook 48 is out of engagement with hook 42 and the collar 78 is in engagement with the lever 80. The spring 44 is effective through the link 50 and its stop collar 78 to force the lever 80 incounterclockwise direction, thereby causing the roller 60 to engage the cam surface 57'. The slope of the cam surface'57' is such that the spring force is effective to create a clockwise turning moment, thereby biasing the door to the right to close the access opening 11 in the oven liner 12.

To move the door to the broil position, illustrated in Fig. 6, the door is pulled to the left. This action causes the roller 60 to ride over the apex portion 59' and into engagement with the cam surface 58'. The bias on the link 50 being still effective upon the lever 80, the roller 60 is now effective to provide a turning moment in counterclockwise direction, urging the door to the left in opening direction until it .reaches the position in which the hook 48 on the link 50 engages the hook 42 of the blade 40. The downward bias on the link is effective through the hook 48 to produce a clockwise turning moment, urging the door 10 to the right in the direction of closing.

Here again, as in the first embodiment, the lost motion in each of the two lost motion connections is taken up when the door is in the broil position, at which time the moment in door-closing direction opposes and balances the moment in door-opening direction to hold the door in the broil position.

Should the door be pulled further outwardly a slight amount and then released, the turning moments mentioned above willv automatically restore it to the desired broil position. As the door is pulled open, the turning moment in counterclockwise or door-opening direction is terminated, so that when the door is released, the clockwise moment will return the door to the broil position, at which time the counterclockwise moment is again applied to oppose the clockwise moment.

To move the door to the fully open position, the door is pulled to the left, passing through the position in Fig. 7. During such motion, the link 50 is forced upwardly against the bias of the spring to counterbalance the weight of the door. Also, during such motion, the stop collar 78 is moved upwardly out of engagement with the lever 80, so that the spring has no effect on the roller beyond the broil position. Thus, it will be seen that the entire effect of the spring bias is now exerted on the door to counterbalance the weight of the same.

When the cam 58' is moved out of engagement with the lever 80, the lever will move counterclockwise until further rotation is stopped by the stud 89, as previously described. The lever 80 is thus positioned for reengagement by the cam surface 58' when the door is moved clockwise to the broil position.

The blade 40' is further provided with an outwardly extending stop portion 79 which limits the fully open 5; position of the door 10. The portion '79 abuts the panel 14 when the door is in the fully open position.

Itwill now be seen that I have provided a simple door positioning mechanism having a minimum number of parts which may easily be assembled together.

It will also be seen that I have provided a positioning mechanism having a single spring providing the bias for counterbalancing the door in the open position, for holding the door tightly closed and for positioning the door in the broil position. The pull on the spring is always in a straight line, regardless of the position of the door, thereby insuring smooth and positive action and substantially eliminating the possibility of seizing or binding.

While the invention has been shown in several forms, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In combination, an oven having a front opening, a door for closing said opening, hinge means for supporting said door at its lower end, said door being movable to a partially open or broil position, means for holding said door in said broil position and in the closed position including a blade fixed to said door and having a first cam portion and a second cam portion of opposite slopes, a roller disposed adjacent said blade, a spring force transmitting member connected to said roller, a spring anchored at one end and having an abutment member at its movable end, said abutment member being adapted to abut said spring force transmitting member and to bias said roller into engagement with said first cam portion when said door is in said closed position to thereby provide a first turning moment urging said door to the closed position, said first cam portion being movable out of engagement with said roller and said second cam portion being movable into engagement with said roller upon opening movement of said door, whereby said first turning moment is terminated and a second turning moment in door opening direction is provided urging said door to the broil position, means for substantially counterbalancing said door, including a lost motion connection for said blade disposed between the free end of said spring and said blade, said lost motion connection being ineffective when said door is in the closed position but being effective to impart a third turning moment on said door in closing direction when said door is moved in opening direction to an open position at or beyond the broil" position, thereby counterbalancing the weight of said door.

2. In combination, an oven having a front opening, a door for closing said opening and movable to a partially open or broil position, hinge means for supporting said door at its lower end for movement about a horizontal axis, means for counterbalancing the weight of the door including a blade fastened to said door, said blade having a free end portion, a spring anchored at one end and having a connecting member at its free end arranged to engage said free end portion of the blade when said door is in the broil position, whereby said spring exerts a first turning moment on said door in closing direction, means for retaining said door in said broil position including a cam portion pro vided on said blade, a roller, a lever supporting said roller adjacent said blade, means for pivotally supporting said lever, said connecting member being provided with an abutment adapted to engage said lever and bias said roller against said cam portion when said door is in said broil position, said cam being sloped to provide a second turning moment on said door in door opening direction, said second turning moment balancing said first turning moment to retain said door in said broil position, said abutment being movable out of engagement with said lever and said connecting member maintain- 7 ing engagement with the free end portion of the blade upon further movement of said door in opening direction, whereby the spring serves to counterbalance the weight of the door in any position beyond the broil position in door opening direction.

3. In combination, an oven structure having a front opening, a door for closing said opening and movable to a partially open or broil position, hinge means for supporting said door at its lower end for movement about a horizontal axis, said door having a blade rigidly fastened thereto, said blade having a cam portion, a roller, a yoke connected at one end to said roller, means for guiding the movement of said roller into engagement with said cam portion, a spring anchored at one end, lost motion means at the other end of said spring for connecting said yoke and said blade to said spring, said yoke having a passage at its other end through which said lost motion means extends, said lost motion means having an abutment portion engaging said yoke and serving to bias said roller into engagement with said cam portion when said door is in the closed position and until it is in the broil position, said lost motion means having a connecting portion engageable with said blade when said door is moved to any posi tion at or beyond the broil position in door opening direction, said abutment portion being moved out of engagement with said yoke to remove the bias on said roller and said connecting portion engaging said blade to exert a counterbalancing force on said door when the door is moved beyond the broil position in opening direction.

4. The structure recited in claim 3 in which said blade is provided with a second cam portion of opposite slope than said first mentioned cam portion, said cam portions being joined by an apex portion, said first cam portion being movable past said roller and said second cam portion being brought into engagement with said roller when said door is moved from closed position to said broil position, whereby a force is exerted on said door in opening direction through said roller, said force in door opening direction balancing the counterbalancing force, whereby said door is resiliently retained in said broil position.

5. In combination, a casing having a front opening, a door for said opening hinged at its lower end for movement about a horizontal axis, an arm mounted for movement with said door and having a cam surface, a cam follower positioned to contact said carn surface, a spring force transmitting member connected to said follower, a spring connected at one end to the casing, abutment means connected to the other end of said spring and movable into engagement with the force transmitting member as the door moves in closing direction, said arm being movable into engagement with said abutment .means upon opening movement of the door, said abutposition in closing direction disengaging the arm from the abutment means, whereby spring force is applied to both the arm and the force transmitting member when the door is in the partially open position, to the arm only when the door is moved in opening direction beyond said partially open position and to the follower only when the door is moved in closing direction beyond said. partially openposition, said cam surface including a first portion which is engaged by the follower when the door is in closed position and during the first part of its movement from closed position to said partially open position andwhich is sloped so that the door is biased to closed position, and including a second portion which is engaged by the follower during a remain ing part of the movement of the door from closed position to said partially open position and while in said partially open position and which is sloped to bias the door in opening direction.

6. In combination, an oven having a front opening, a door for said opening hinged at its lower end for movement about a horizontal: axis, an. arm mounted for movement with said door and having a cam surface, a cam follower positioned to. contact the cam surface, a spring having a stationary end and free end, abutment means secured to the free end of the spring, a spring force trans.- mitting member connected to said follower, said abutment means having one abutment which engages said force transmitting member when the door is in closed position and in. a predetermined partially open or broil position and any position therebetween to apply spring force to bias. said follower into engagement with said cam surface, said cam surface including a portion which is engaged by the follower when the door is in closed position and during the first. part of its movement from closed. position to the broil position and which is sloped so that the door is biasedv to closed position, and including a second portion which is engaged by the follower during a remaining part of the movement of the door from. closed position to said broil position and while in said broil position and which is. sloped to bias the door in opening direction, said one abutment being disengaged from the force transmitting member when the door is moved between the broil position and the full open position, said abutment means having a second abutmentwhich efiects a connection with the door arm, when the door'isin said broil position, to apply spring force to the door armbiasthedoor in the direction of door closing in order to counterbalance the spring force applied. through said one abutment when the door is in the broil position, said secondabutment also being effective, in any positionof the door between the broil position and the full open position, toapply spring force on the door in. the direction of closing and beingineifective when the door is closed. and during itsmovement from the closed to, the broil position.

References Cited in the file of this patent UNITED STATES PATENTS 2,063,376 

